Water Vapor

In the framework of the European Union SEa Level Fluctuations (SELF) I and the SELF II Projects designed to study sea level variations around the Mediterranean and Black Seas, the Global Positioning System (GPS) technique was adopted to measure the ongoing crustal movements at tide gauge stations. Tide gauges measure sea-level variations with respect to a ground benchmark. In order to determine true sea-level variations of a few millimeters per year, it is necessary to estimate the ground vertical movement to a high degree of accuracy. Countries involved in the projects were Spain, France, Italy, Greece, Bulgaria and Russia. In the period from 1993 to 1998 repeated observations at more than 28 tide gauges and at a number of reference and intermediate stations were conducted. GPS measurements were complemented by Water Vapor Radiometers (WVR) at selected sites. Individual campaigns were evaluated and analyzed and showed height variations in the millimeter–centimeter range. All data were processed following common standards using the Bernese Software in a unified analysis to generate a combined solution. Based on the normal equations of all of the campaigns, a combined solution for the SELF Projects sites was generated. In the analysis of multi-technique anchor sites to the International Terrestrial Reference Frame ITRF97, it is shown that vertical rates of different techniques may be of different sign with respect to each other and also with respect to the ITRF97 combination. Vertical rates are not reliable in general and even the restriction to the use of long the long-time series sites KOSG, ONSA, WTZR, MADR, GRAZ and MATE did not ensure significant and unique vertical rates. Nevertheless, they had to be used for the reference frame definition. The results of repeated gravity observations and the continuous GPS observations at Porto Corsini and Medicina were compared to the epoch-wise GPS campaigns and revealed that the vertical rates are in conformance with each other if taken over the same period in time. The impact of the WVR observations on tide gauge position variation estimation is shown to improve the vertical component in the case of baseline-wise observations with two WVRs by up to 50%. It is shown, that the time span is too short for epoch-type observations to resolve significant height variations. The estimated rates of about 0–20 mm/year are most likely explained by systematic and random errors in the GPS observations. The absolute gravity observations at selected tide gauges are accurate to ±3 μGal and are in general agreement with the zero result from GPS. The main outcome of the SELF campaign observations therefore was the determination of a homogeneous zero-epoch data set and the creation of a database that includes the complete link from the GPS sites to the sea level in the five Mediterranean countries involved.

Regeneration of irradiated and actual spent solvent (30% TBP in a hydrocarbon diluent) by overheated steam distillation was studied in batch experiments. The hydrodynamic and extraction-backwash parameters of thus regenerated solvent are practically the same as those of the fresh solvent. The bottoms comprise 3-7% of the initial volume and consist essentially of TBP. Large-scale rig trials of the single-

Seed hulls (or coats) of peanut, soybean, cottonseed, lupine, broad beans, and sunflower seeds, were subjected to various treatments in order to get adsorbing carbons. Characterization of porosity was determined by N2/77 K adsorption isotherms. Simple pyrolysis at 500 °C yields low adsorbing carbons of meso-/macroporous character, whereas steam activation of these chars at 850 °C enhances porosity, in micropores, to a limited extent. Chemical activation with H3PO4 at 500 °C exerts the best recommending influence in producing high adsorbing carbons with evenly distributed porosity within micro-mesopore ranges. It was found that phosphoric acid activation of the studied precursors enhanced the yield, surface area and pore volume; 32–46%, 437–1022 m2/g and 0.444–0.809, respectively, as compared to other treatments. The capacity to remove methylene blue, in single bottle experiments, complements the state of porosity deduced from the gas phase adsorption of N2. Peanut shells proved the best feasible raw material under all treatment processes, whereas lupine seeds and sunflower seed hulls show relatively the least affected. Dye removal capacity was enhanced by carbon mesoporosity, whereas adversely affected by its increased surface pH and ash content was observed. Low-cost by-products of oil producing industry seem, thus, to be promising precursors for the production of highly valuable adsorbing carbons.Figure shows the nitrogen adsorption isotherms of some selected carbons and displays type II isotherms, indicating that the prepared carbons with a mixed porosity character (micro-/mesoporous).► Our current research aimed at preparation and characterization of micro-mesoporous carbons from local and renewable seed hulls such as peanut, lupine, sunflower, cotton seed, soy bean, etc. ► Various treatment schemes were applied as simple pyrolysis, steam activation and phosphoric acid activation. ► The findings were shown that chemical activation with H3PO4 at 500 °C proved to be the most recommending procedure as it leads to low ash, high yield and good quality adsorbing carbons with mixed micro-/mesopores.

A model of atmospheric photochemistry and transport has been developed and applied toward investigating global tropospheric chemistry. The Model of Atmospheric Transport and Chemistry - Max-Planck-Institute for Chemistry version (MATCH-MPIC) is described and key characteristics of its global simulation are presented and compared to available observations. MATCH-MPIC is an "offline" model which reads in gridded time-dependent values for the most basic meteorological parameters (e.g., temperature, surface pressure, horizontal winds), then uses these to compute further meteorological parameters required for atmospheric chemistry simulations (convective transport, cloud microphysics, etc.). The meteorology component of MATCH-MPIC simulates transport by advection, convection, and dry turbulent mixing, as well as the full tropospheric hydrological cycle (water vapor transport, condensation, evaporation, and precipitation). The photochemistry component of MATCH-MPIC represents the major known sources (e.g., industry, biomass burning), transformations (chemical reactions and photolysis), and sinks (e.g., wet and dry deposition) which affect the O3hyphen;HOx-NOy-CH4-CO photochemical framework of the "background" troposphere. The results of two versions of the model are considered, focusing on the more recent version. O3 is in relatively good agreement with observed soundings, although it is generally underestimated at low levels and overestimated at high levels, particularly for the more recent version of the model. We conclude that the simulated stratosphere-troposphere flux of O3 is too large, despite the fact that the total flux is 1100 Tg(O3)/yr, whereas the upper limit estimated in recent literature is over 1400 Tg(O3)/yr. The OH distribution yields a tropospheric CH4 lifetime of 10.1 years, in contrast to the lifetime of 7.8 years in the earlier model version, which nearly spans the range of current estimates in the literature (7.5-10.2 years). Surface CO mixing ratios are in good agreement with observations. NO is generally underestimated, a problem similar to what has also been found in several other recent model studies. HNO3 is also considerably underestimated. H2O2 and CH3OOH, on the other hand, are in relatively good agreement with available observations, though both tend to be underestimated at high concentrations and overestimated at low concentrations. Possible reasons for these differences are considered.

To develop a gentamicin-loaded wound dressing, cross-linked hydrogel films were prepared with polyvinyl alcohol (PVA) and dextran using the freezing–thawing method. Their gel properties such as gel fraction, swelling, water vapor transmission test, morphology, tensile strength, and thermal property were investigated. In vitro protein adsorption test, in vivo wound healing test, and histopathology were performed. Dextran decreased the gel fraction, maximum strength, and thermal stability of hydrogels. However, it increased the swelling ability, water vapor transmission rate, elasticity, porosity, and protein adsorption. The drug gave a little positive effect on the gel properties of hydrogels. The gentamicin-loaded wound dressing composed of 2.5% PVA, 1.13% dextran, and 0.1% drug was more swellable, flexible, and elastic than that with only PVA because of its cross-linking interaction with PVA. In particular, it could provide an adequate level of moisture and build up the exudates on the wound area. From the in vivo wound healing and histological results, this gentamicin-loaded wound dressing enhanced the healing effect more compared to conventional product because of the potential healing effect of gentamicin. Thus, this gentamicin-loaded wound dressing would be used as a potential wound dressing with excellent forming and improved healing effect in wound care.

Positive trend of the North Atlantic Oscillation (NAO) during last several decades was also accompanied by a positive trend of the East Atlantic Western Russia (EAWR) pattern. Decline of the Mediterranean precipitation during the period has also been noted. The precipitation decline over the western part of the region has been linked to the positive trend of the NAO. Explanation for the precipitation decline over the eastern Mediterranean by the role of the EAWR trend has also been suggested. An evaluation of the hypothesis is performed in the current study. A methodology for the determination of the characterizing typical low troposphere circulation during wet-months large-scale correlation-circulation patterns is suggested. The large-scale circulation patterns for three target areas over the northwestern, north-eastern, and southeastern Mediterranean regions are constructed separately for the low and high phase periods of the teleconnection regimes. According to the results, the precipitation decline over the Mediterranean region during the last several decades of the past century is explained by the positive trend of the EAWR, which in its turn was induced by that of the NAO. The trends have lead to the changes in the typical for the wet periods of the year low-troposphere circulation regimes associated with a decline in the water vapor transport from Atlantic.

Polyvinyl alcohol (PVA), PVA crosslinked with glutaraldehyde hydrogels (PVA/GA), PVA with tetraethylorthosilicate (PVA/TEOS) and PVA/GA/TEOS hybrids with recombinant MPB70 protein (rMPB70) incorporated were chemically characterized by Fourier transform infrared spectroscopy (FTIR). FTIR spectra of PVA hydrogel samples showed the absorption regions of the specific chemical groups associated with poly(vinyl alcohol) (–OH, –CO, –CH2) and PVA/GA confirming the formation of crosslinked hydrogel (duplet –CH). It was observed C–H broad alkyl stretching band (n = 2850-3000 cm-1) and typical strong hydroxyl bands for free alcohol (nonbonded –OH stretching band at n = 3600-3650 cm-1), and hydrogen bonded band (n = 3200-3570 cm-1). The most important vibration bands related to silane alcoxides have been verified on FTIR spectra of PVA/TEOS and PVA/GA/TEOS hybrids (Si–O–Si, n = 1080 and n = 450 cm-1; Si–OH, n = 950 cm-1). FTIR spectra of f PVA hydrogel with rMPB70 incorporated have indicated the specific groups usually found in protein structures, such as amides I, II and III, at 1680-1620 cm-1, 1580-1480 cm-1 and 1246 cm-1, respectively. These results have given strong evidence that recombinant protein rMPB70 was successfully adsorbed in the hydrogels and hybrids networks. These PVA based hydrogels and hybrids were further used in immunological assays (Enzyme-Linked Immunosorbent Assay – ELISA). Tests were performed to detect antibodies against rMPB70 protein in serum samples from bovines that were positive in the tuberculin test. Corresponding tests were carried out without PVA samples in microtiter plates as control. Similar results were found for commercially available microplates and PVA based hydrogels and hybrids developed in the present work regarding to immunoassay sensitivity and specificity response.

Vanadium-containing mesoporous silicas (V-MS) have been synthesized with primary amines as templates and characterized using spectroscopic techniques. Vanadium could be incorporated into the silica framework up to a content of about 2.5 wt.-% without formation of significant amounts of vanadium oxide after calcination. The dimensions of the mesopores of the structures increased from 25 to 35 Å with the alkyl

A total of 198 precipitation samples were collected at Nagqu on the central Tibetan Plateau in 2000. Based on the isotope data from individual samples, the local meteoric water line was established: δD = 7.7δ18O–4.6 (r 2 = 96, p < 0.0001). Stable isotope data from precipitation exhibit a seasonal variability in deuterium excess. The study indicated that the influence of moisture transport and recycling on seasonal variation of d-excess in precipitation events is potentially significant. During summer precipitation, the lower d-excess values are usually related to warm and humid Indian Ocean moisture transport. In spring and winter, due to the cold and dry westerly and northern moisture transport, d-excess values in precipitation are usually higher. The d-excess in summer precipitation is also influenced by the secondary evaporation between cloud base and ground during precipitation events, as well as the admixture of water vapor from evapotranspiration over the continent along the storm trajectories. The results also suggested that the d-excess values in precipitation at Nagqu displayed an obvious transition due to its location on the central Tibetan Plateau.

Freeze-drying is a low-pressure, low-temperature condensation pumping process widely used in the manufacture of pharmaceuticals for removal of solvents by sublimation. Key performance characteristics of a freeze-dryer condenser are largely dependent on the vapor and ice dynamics in the low-pressure environment. The main objective of this work is to develop a modeling and computational framework for analysis of vapor and ice dynamics in such freeze-dryer condensers. The direct Simulation Monte Carlo (DSMC) technique is applied to model the relevant physical processes that accompany the vapor flow in the condenser chamber. Low-temperature water vapor molecular model is applied in the DSMC solver SMILE to simulate the flowfield structure. The developing ice front is tracked based on the mass flux computed at the nodes of the DSMC surface mesh. Verification of ice accretion simulations has been done by comparison with analytical free-molecular solutions. Simulations of ice buildup on the coils of a laboratory-scale dryer have been compared with experiments. The comparison shows that unsteady simulations are necessary to reproduce experimentally observed icing structures. The DSMC simulations demonstrate that by tailoring the condenser topology to the flow-field structure of the water vapor jet expanding into a low-pressure reservoir, it is possible to significantly increase water vapor removal rates and improve the overall efficiency of freeze-drying process.

Nanohybrid thin films consisting of titania nanoparticles embedded in a suitable polymer matrix represent a new class of functional materials for optoelectronic applications. For instance, our previous studies show that titania-poly(methylmethacrylate) or TiO2-PMMA nanohybrids derived from in situ sol-gel technique are promising as nonlinear optical materials since they can demonstrate a very fast recovery time of ∼1.5 picosecond and a large third-order nonlinear susceptibility, χ(3) up to 1.93 × 10−9 esu, as observed by pump-probe and Z-scan techniques. However, it was realized that the conventional in situ sol-gel technique employed led to a largely amorphous TiO2 phase in the PMMA matrix. In order to overcome this limitation, we have performed two modification approaches making use of high pressure water vapor, i.e.: pre-and post-hydrothermal treatments applied on the sol-gel precursors. The degree of TiO2 crystallinity in the resulting nanohybrids was studied by XRD, FTIR, and TEM. Both approaches can enhance the nanocrystallinity TiO2 phase considerably and at the same time preserve the integrity of polymer matrix. It was found, however, that while the nanohybrid thin films derived from the pre-hydrothermal treatment show a high absorption in the visible length, those derived from the post-hydrothermal treatment are highly transparent. Nonlinear optical measurement using the Z-scan technique on the latter sample shows a significant enhancement in χ(3) as high as 5.27 × 10−9 esu.

Purpose Use RH-perfusion microcalorimetry and other analytical techniques to measure the interactions between water vapor and amorphous pharmaceutical solids; use these measurements and a mathematical model to provide a mechanistic understanding of observed calorimetric events. Materials Isothermal microcalorimetry was used to characterize interactions of water vapor with a model amorphous system, spray-dried raffinose. Differential scanning calorimetry was used to measure glass transition temperature, T g. High-sensitivity differential scanning calorimetry was used to measure enthalpy relaxation. X-ray powder diffraction (XRPD) was used to confirm that the spray-dried samples were amorphous. Scanning electron microscopy (SEM) was used to examine particle morphology. Gravimetric vapor sorption was used to measure moisture sorption isotherms. Thermogravimetric analysis (TGA) was used to measure loss on drying. Results A moisture-induced thermal activity trace (MITAT) provides a rapid measure of the dependence of molecular mobility on moisture content at a given storage temperature. At some relative humidity threshold, RHm, the MITAT exhibits a dramatic increase in the calorimetric rate of heat flux. Simulations using calorimetric data indicate that this thermal event is a consequence of enthalpy relaxation. Conclusions RH-perfusion microcalorimetry is a useful tool to determine the onset of moisture-induced physical instability of glassy pharmaceuticals and could find a broad application to determine appropriate storage conditions to ensure long-term physical stability. Remarkably, thermal events measured on practical laboratory timescales (hours to days) are relevant to the stability of amorphous materials on much longer, pharmaceutically relevant timescales (years). The mechanistic understanding of these observations in terms of enthalpy relaxation has added further value to the use of RH-perfusion calorimetry as a rapid means to characterize the molecular mobility of amorphous solids.